Discussion on: Daily Challenge #210 - Separate Capitalization

[Valts Liepiņš]

Solution in Haskell using folding:

import Data.Char (toUpper)

capitalize :: String -> [String]
capitalize str = folder skipCase <$> [("",0),("",1)] <*> pure str
  where
    folder fn init = fst . foldr fn init
    skipCase :: Char -> (String, Int) -> (String, Int)
    skipCase c (cs, i) | i `mod` 2 == 1 = ((toUpper c):cs, i+1)
                       | otherwise      = (c:cs, i+1)

The skipCase folding function takes care of upcasing every 2. letter. The folder is a makes it easier to map the function over both capitalization variations, which then can be applied to the input string.